England adopted the policy of selecting only domestically based players following next year's World Cup after learning that French clubs were lining up to sign many of their top stars when their current club deals expire.

The Rugby Football Union chief executive, John Steele, has sent a letter to players and agents saying that England intends to select only from Premiership clubs after the 2011 World Cup and that anyone who moved abroad would be jeopardising their international careers.

Jonny Wilkinson, Tom Palmer and James Haskell are the three England elite squad players earning their livings in France, while Andrew Sheridan, who is out of contract at Sale next summer, is a target for Toulon. All except Haskell, who was not available for comment today, are in their 30s, unlikely to be in contention for a place in the 2015 World Cup squad.

Players coming out of contract in the summer will be able to talk to potential employers from next month. The England tight-head, Dan Cole, who has again attracted interest from French clubs, has yet to sign a new deal with Leicester and the RFU's stand last week was less a proclamation than a pre-emptive strike, with Courtney Lawes, Ben Foden, Dylan Hartley, Chris Ashton and Ben Youngs understood to be among the star names being targeted by French clubs.

"England have a crop of exciting young players and they are attracting the interest of French clubs," said one agent today. "I know that the likes of Lawes, Hartley, Cole, Foden and Youngs will have no shortage of offers from France when they come out of contract and I can understand the RFU's desire to ensure that they all remain in the Premiership. England's stand of not selecting players who earn their livings outside the country might not be in accordance with employment law, but it is adopted by New Zealand and Australia, and Wales have a similar policy.

"The bottom line is that French clubs have money, and although the Top 14 has introduced a salary cap this season, there are a number of ways of getting around it, not least by sponsors paying players for appearances as a wage top-up.

"It is different for players who are in their thirties. For someone like Andrew Sheridan, next summer probably marks his last big club contract. Where there could be a problem is if a player takes a wage cut to either return from France or stay in England and then finds himself not selected in the national squad. He would lose out financially but there would be no compensation."

French clubs are being aggressive in their pursuit of players because the old order in the Top 14 has been thrown into turmoil by the emergence of the likes of Toulon, Racing Métro and Montpellier. No longer do Toulouse, Stade Français, Biarritz, Clermont Auvergne and Perpignan dominate. Even Bayonne write big cheques.

The RFU's director of elite rugby, Rob Andrew, said: "We've got a number of very talented young English players coming through the system and we really feel that we want to keep them playing in England, both for our clubs and also for the national team. We're not saying players can't go: it's a free world. It's about saying to them that we think in the long run we can help protect their international careers if they play for our English clubs. We have said in exceptional circumstances we will look at it, clearly. We're not going to cut off our nose to spite our face but we don't want an exodus of our best young players going across to play in France because it will cause us difficulties."

England's proposed policy has not impressed the Stade Français president, Max Guazzini, who has James Haskell, Tom Palmer and Ollie Phillips on his books. "England accept our international players who go over there, but not the opposite," he said. "I won't take any more English players, which is regrettable. This is the protectionist side of the English coming out."

The Toulon president, Mourad Boudjellal, does not believe the policy will affect his chances of persuading Jonny Wilkinson to sign a new contract. "This isn't really a problem because the RFU specified that this decision will be applied except in exceptional circumstances," he said. "I am confident we will keep Wilkinson."

The Leicester director of rugby, Richard Cockerill, believes French clubs will not be disheartened by the policy. "Having guys all year round and not losing them in the international windows might be an attraction," he said. "Northern hemisphere sides generally buy players from the southern hemisphere because they are good and are available all year round. English players in the twilight of their careers might decide to go to France for the financial rewards."

The Rugby Players' Association chief executive, Damian Hopley, has warned England's stance on not selecting players based abroad could be challenged under European law. Hopley said: "Clearly we want the best players to be available to play for England but this approach could be seen as heavy-handed. I understand the intentions behind the approach but there are a lot of people in the game who are nervous about the execution and practice of what is being requested. I am sure the stance is eminently challengable if a party wanted to take it further. We all have to be realistic about EU legislation and if there is a restraint on a player it goes to the heart of freedom of movement for our members."